Generally, while traveling on the ground, the computer, for example a guidance computer of the aircraft, which computes the guidance commands, determines the lateral deviation and the lateral speed of the aircraft with respect to the axis of the runway, using the signal of a “Localizes” (LOC) beacon of an instrument landing system of the ILS (“Instrument Landing System”) type. This signal is supplied to it by a multimode receiver of the MMR (“Multi Mode Receiver”) type. This signal gives, in the nominal case, an estimation of the position with respect to the center of a beam which is supposed to be collinear with the axis of the runway. However, this signal can be interfered with and such an interference has a direct impact on the estimated position and speed of the aircraft and therefore on the guidance on the ground. In general, the interferences exhibit only high frequency components, which have less impact on the guidance (because they are easily manageable by a computer). However, it can occur that low frequency noises appear on the MMR data coming from the multimode receiver. This can occur, for example, if the engine speed has the same frequency as the LOC signal, if a vehicle passes in front of the LOC beacon, or if a building reflects the signal. In these cases, the multimode receiver of the MMR type sends the sum of the two signals. The usual use of the multimode receiver for estimating the lateral speed and the lateral position is not therefore optimal in all situations.